Method of manufacturing tubes



Dec. 25, 1945. G. E.' BARNHAR-r METHOD OF MANUFACTURING TUBES Filed March 8, 1943 2 Sheets-sheet 1 Y vide an improved method novel method of Patented es. 194s l estL-lss a METHOD F MANUFAGTBING TUBES George E. Bankett. Pasadena Calif.

This invention relates to a method for manufacturing tubes. The general object of the'inventlon is to prowhereby tubes may be operated upon to vary the thickness of different portions of the tube.

diameter and/or wall the upper plate il A more specific object oi the invention is to A provide a novel method for making a tube by means of which the-tube may be provided with thickened wall portionswhich may be arranged at the ends of the tube.

A further object of my invention is to provide a working a structure of the tube is improved.

Other objects and advantages/tof the inveution will be apparent from the following description taken in connection with the accompanying drawings, wherein:

Fig. 1 is a side elevation, with parts in section, showing my improved apparatus:

Fig. 2`is a view similar to Fig'. l showing the parts in another position:

Fig. 3 is tube from which my improved tube is made;

Fig. 4 is a central sectional members with the tube therein and with one end of the tube expanded and with a headed member in position for movement;"

Fig. 5 is a view similar t0 F13. '4 after the headed member has passed through the intermediate portion of the tube;

Fig. e is e view similar-to m. 4 snowing the tube reversed and being pulled through thedie to reducethe external diameter and to thicken the wall portion of one end portion of the tube. and

Fig. 'l is a view similar to Fig. 4 showing the other end of the tube reduced in diameter and its wall thickened.

Referring to the drawings by reference acters I have shown my invention a's embodi a tube working apparatus which is indicated generally at iii. The apparatus includes a frame Il charview showing die 1 ed in tube so that the grain a central sectional view through a l ity indicated gen Appueauoa Mum s, me. sensi no. 41am 4 cream. v(ci. za-issi an aperture in the membe and normally` holds the plate il and thedie portion 2e in elevated above the die portion It The rods It below the lower member i5 are connected by a plate 28 to which a plunger rod uis connected. Y

rod 24 has a piston 2l thereon, in a cylinder 2|. The cylinder into engagement with the die It. ton 2l is released thev spring to its wim position.

In the practice of which may be made of aluminum, steel. copper or other suitable material@ This tube preferably has a substantially uniform lwall thickness and is preferably of substantially uniform diameter throughout. The tube may' be of any suitable length.

The die members When the pis- Il and 2l together form a cav. rally at Il. This cavity includes an intermediate portion I2 which is cylindrlcai and the diameter of which is slightly greater than the exterior diameter of the tube il. so that a small annular space between the exterior of the tube v cent die wall. At its front end the die cavity 3| and l5. The portion Il is counectedwith theV portion truste-conical portion 3| andthe-portions 3l and Il are connected by a frusta-conical portion 31.

drical portion nem m place by supports n. 'rue mme u mcludes an upper member i. end members il and a bottom member i5.

0n the bottom member ii I arrange the lower half It of a die which is heldin place by fastening members i1. Rods il are mounted to slide through apertures in the bottom member il and at their top are connected by a plate I! on which the upper h alf 2l of the die is held in place by fastening members Il. The upper end of a spring 22 engages a support 22a while the'lower end of which works in thesprinaengagesapinbwhichpueelthroulh il is of ternal diameter of the tube Il.

si includes a cylin- 'frusto-conical portion il! According to the manufacture of mandrel III' (Fiss. l and 2) into one "endof i a tube in the die. The m'andrel portions ll and il. The mandrel also includes a' tip B8 which substantially the 'same Il is mounted-on a piston rod Il the cylinder Il. 'The lcylinder Il includes a partition "and the pistourod Il includes a head II which reciprocatee in the cylinder due to action of 'hydraulic huid in tbe cylinder l controlled by means not shown.

The cylinder il is mountedY on parallel links Il so that it may move shownin Fil. 1 to the this figure. The links The mandrel full line position shown in Il are moved by meansof unanswered position 22 willreturn the die my invention I ltake a tube 3i Y is provided and the adia- 38 connected tothe portion I2 by a' disclosure'r first step in the thetubeconsistsl'of inserting a includes-portions Il and il vwhich correspond to the die diameter as the irlfrom the dotted lin'e position apistonrod-tl havinganend portion workingin a slot 2 in one of the links il. The piston rod Il includes a head Il arranged in a cylinder Il and it is operated hydraulicallyv by means not shown.

In operation the piston 63 is actuated to raise the cylinder Il to its upper position whereupon the piston l1 is operated to force the mandrel Ill f y into the tube III. These actions occur after the piston 25 has been actuated to `cause the die members to move together to the position shown in Fig. 4.

To prevent the tube Il from being-forced from the die by the mandrel Il, I provide a stop member 1l which is mounted on a piston 1| in a cylinder 12 which is supported by links 13. When the piston 1| is in the forward position, as shown by solid lines in Fig. l. the stop member Il engages the inner end of the tube 30 and holds the tube in place.

The cylinder 12 is moved to inoperative position by a piston rod 1I the free end of which works in a slot 1l in one'of the arms 13. The piston rod 14 has a head 18, which reciprocates in a cylinder 11. When the piston 1I is in its retracted position, as shown in full lines in Fig. 2, the cylinder done by means of a piston rod I1 which has an end portion working in a slot 88 in one of the arms I6. The rod l1 has a piston 89 thereon which works in a cylinder III. The piston rod 81 is continued at al and has an endportion which works in a vslot l2 in a pivoted arm -93. The arm 92 supports a flanged roller 84 and the construction is such that the links 86 and 90 will move from the solid line position in Fig. 2 to the dotted line position in this figure when the piston 89 is actuated. The cylinder 85 has a piston 85 therein which is connected to a rod 96. I'he rod 98 has a clutch member l1 thereon, the details of which form no part of this present invention. The clutch member l1 releasably engages a head 98 of a come-along rod 90 which has a head |00 thereon. 'I'he come-along rod 89 is supported by the roller 94 previously described. The flanges of the roller 8l, when the parts are in the position shown in Fig. 1, straddles the cylinder Il.

When the parts are in the position shownin Fig. 2 and the piston Il moves forward in its cylinder 85, the rod Il will advance, pushing the come-along rod 99 through the tube m the die, whereupon the grip portion I Il on the forward end of the come-along will be engaged by a clutch member |02 on a come-along |03. The come-along is mounted on ways IM so that 'it may be moved from the position shown in Fig. 1 to the position shown in Fig. 2. The details of construction of the come-along form no part of the present invention.

After the clutch member I l2 engages the rod portion ill the come-along is operated thus pulling the head member Ill through the tube. 'I'he diameter of the member plus twice the wall thickness of the tube Il is slightly greater than 12 is raised to an inoperative Vner face of the die and the drawing method describedresults in an improved grain. As the end l0 advances the material adjacent thereto moves outwardly and into engagement with the portions n and n of the die so that the end of the tube assumes the position shown in Fig. 5. 'I'he above described steps provide a tube having enlarged l stepped end portions and a cylindrical intermediate portion.

'I'he die parts are then separated and the tube removed. The end of the tube formed by the largest portion oi' the mandrel 50 is then chamfered as at H0, Fig. 6, as by spinning, and a pull member III is run through the tube. The pull member has a head Ii2 which engages the cham fered portion and at the end remote from the head has a head portion i i3. The tube is then placed in the ldie with the end 80 of the tube directed towards the portion 3l of the die and the die is closed.'

so The head H2 is then' engaged by the clutch member 01 and the piston is operated to pull the pull member III throughthe die. As the rodmoves the tube is ypushed through the die along with the rod. The end portion In of the sa tubeilrst engages the conical portion 39 oi' the die and as the tube advances its diameter is decreased as it passes through the die. This action .continues with the portions of the tube formed by the die parts 3|, 24, 31l and 35, in the order 40 named, engaging the part 39 of the die and having their respective diameters reduced. As a result the larger end of the tube previously formed by the mandrel is reduced in diameter as shown Iat m, Fig. 7.

The steps described produce a tube having an intermediate portion and having end portions of greater wail thickness than the intermediate portion and with the exterior diameter of the tube uniform throughout.

From the foregoing description it will be apv parent that I have invented a novel method for making tubes which is highly efficient for its intended purpose.

Having thus described my invention, I claim:

1. The method of making a tube comprising taking a tube, expanding one end portion of the tube-and decreasing the wall thickness of thel one end portion of the tube. causing an intermediate portion of the tube to expand in diameter -snd limiting the amount of diametrical expansion of the intermediate portion of the tube so that it is ot less diameter than Ithat of the one end portion of the tube, causing the other end portion of the tube to expand more than said intermediate portion expands while limiting the amount of expansion of said other end portion of the tube and thereafter reducing the external diameter of each end portion of the tube to equal the external diameter of the intermediate portion of the tube.

2. The method of making a tube comprising taking a tube; expanding one end portion of the tube and decreasing the wall thickness ofthe one end portion of the tube, holding the one end portion of the tube against axial movement, causing of uniform wall thick-ness 3. The method of making a tube comprising taking a tube which is of substantialuniform dlameter and substantial uniform wall thickness throughout, expanding one' end portion oi the I tube and decreasing the wall thickness of the one end portion of the tube, holding the one end portion of the tube against axial movement, causing an intermediate portion of the tube to expand in diameter while limiting the amount of diametrical expansion of the intermediate portion of the tube so that it is of less diameter than that of the pand more than said one one end portion of the tube, causing the other end portion of the tube to expand more than said intermediate portion expands while limiting the amount of expansion of said other end portion o! the tube and thereafter reducing the'external diameter of each end portion of the tube to equal the external diameter of the intermediate portion o! the tube'.

4. The method of making a tube comprising taking a tube, holding the tube against axial movement, causing one portion of the tube to expand in diameter while limiting the amount of diametrical expansion of the one portion' of the tube, causing another portion of the tube to exportion expands while limiting the amount of expansion of said other portion of the tube, and thereafter reducing the external diameter of said other, portion of the tube to equal the' external diameter of the one portion of the tube.

GEORGE E. BARNHART. 

